change registrants metadata and workflow: right now no more status field but a little bit more complex workflow that handle also waiting list
change readme
some modification to the mailer that notify subscription to the user; some modification to the view in order to add a new button that allow manager/contributor to add registrant in a closed form; fix some translations
update readme
fix some chaos with branches
Merge branch 'removestatus'
align the workflow on file system with the one in the site